Question

(Molecular Biology) Define the following components of replication: polymerase, helicase, DNA ligase, RNA primase, and ssDNA binding proteins.

Answer 1

Polymerase : The polymerase enzyme involved in replication is DNA POLYMERASE. The DNA polymerase is an enzyme that synthesizes DNA molecules from deoxyribonucleotides, which are the building blocks of DNA. These enzymes are essential for DNA replication and they work in pairs to create two identical DNA strands from a template DNA strand. During the process, DNA polymerase reads the template DNA strands to create two new strands that matches existing ones. The two main DNA POLYMERASES involved in replication are : DNA POL III and DNA POL I.

Helicase : The Helicase plays an important role in replication by unwinding the DNA Strand. DNA helicase is an enzyme that breaks the hydrogen bonds that hold the DNA into the double helix structure. The place at DNA where DNA helicase unzips the DNA is known as a replication fork.

DNA LIGASE : DNA ligase is an enzyme which facilitates the joining of DNA strands together by catalyzing the formation of a phosphodiester bond. The gaps between the DNA fragments are sealed by DNA LIGASE.

RNA PRIMASE : The RNA PRIMASE is an enzyme which synthesizes short RNA sequences called primers.  The RNA PRIMER are short stretches of nucleic acid complementary to the template, that provides a 3' end for DNA polymerase to work upon. Typically, a primer is about five to ten nucleotides long.

ssDNA Binding Proteins : The single-stranded binding proteins coat the separated strands of the DNA near replication fork which helps in keeping them from coming back together into a double helix. It prevents the DNA from rewinding.